Processes for the oxidation of organic compounds such as hydrocarbons in the presence or absence of catalysts are well known. There is continuing applied research activity devoted to achieving economically feasible oxidation processes for commercial scale operation.
Numerous oxidation catalysts have been reported in the prior art, such as are disclosed in U.S. Pat. Nos. 2,904,580; 3,142,697; 3,179,694; 3,197,419; 3,198,750; 3,200,081; 3,200,084; 3,226,421; 3,248,340; 3,264,225; 3,251,900; 3,257,474; 3,260,768; 3,668,245; 3,702,868; 3,703,550; 3,856,824; 3,859,358; and the like.
Acetic acid is generally produced by the carbonylation of methanol or by the oxidation of acetaldehyde or hydrocarbons.
U.S. Pat. No. 3,282,994 describes a method for the oxidation of butane in liquid phase. U.S. Pat. No. 3,607,925 provides a process for the production of acetic acid by oxidation of butene-2 with nitric acid in the presence of a vanadium catalyst. U.S. Pat. No. 3,644,512 discloses a process for converting butane to acetic acid in liquid phase in the presence of a soluble cobalt compound.
Processes for the oxidation of hydrocarbons in the vapor phase by means of oxygen-containing gases have not proven entirely satisfactory primarily due to the excessive formation of undesirable carbon oxides, and to the difficulty in maintaining control of the highly exothermic oxidation reaction. U.S. Pat. No. 3,395,159 provides an improved process wherein the oxidation of hydrocarbons is performed in a reactor system having fused vanadium oxide catalyst coated on the inner surface of the reactor, which system has the advantage of better control and isothermal operation.
It is also known that it is possible to oxidize catalytically in vapor phase lower olefins into acetic acid and a high proportion of carbon oxides.
In practice the commercial processes for oxidation of hydrocarbons are difficult to manage, and inevitably the yield of desired product is low in comparison to the yield of carbon oxides and other oxidation by-products.
Accordingly, it is an object of the present invention to provide a commercially feasible process for oxidation of hydrocarbons.
It is another object of this invention to provide a vapor phase process for converting C.sub.4 -hydrocarbons into acetic acid.
It is another object of this invention to provide a process for oxidizing butane to acetic acid with high conversion efficiency and with a low yield of organic by-products.
Other objects and advantages shall become apparent from the following description and examples.